According to an April, 2009 FDA study neither cell phones nor cordless phones emit enough radio frequency radiation to cause brain tumors or any other health risks. Although no study to date has made a correlation between the use of these devices and brain tumors, some researchers are recommending that children should not be aloud to have contact with them for more than 1 hr per day. Since cell phone use exploded in the 1990's, there are not enough long-term studies to know the long-term effects on children. Cell phones and cordless phones emit low levels of nonionizing radiation which is not toxic. Ionizing radiation is found in CT Scans and radiation therapy for certain types of brain tumors. So it doesn't really matter whether a cell phone or a cordless phone emit different levels of rf radiation. Neither devices are harmful.

Cordless phones operate at a much lower radio frequency than cel phones that radiate microwave signal. Power output of cordless phones are relative lower as it is used at short distances from the receiving unit. Thus, cordless phones has less radiation.

Cordless phones give off larger amounts of radiation than cellphones.

http://www.cure-guide.com/Natural_Health_Newsletter/Cell_Phone_and_Cordless_Phone_/cell_phone_and_cordless_phone_.html

Any time you get your information from a single source you run the risk of being misinformed. I encourage you to investigate the links below and do your own research on brain cell damage and cancer associated with cell phone/cordless phone use -- if not just for yourself, do it for your children and your family -- Do you care about them enough to spend 10 minutes of research that could keep them safe and healthy?

The supposed "best answer" given by Komomai pretends to speak from a position of authority. It contains many fallacies like "there are not enough long-term studies" to know the effects of years of cell phone use -- that statement is patently false. Read the article below about studies conducted by researchers in Sweden that found that regular cell phone use (1 hour per day) produces a 6 times higher risk of malignant brain tumors. The tumors frequently occurred on the side of the head to which the cell phone was held.
Here’s a quote from Professor Kjell Mild in the International Journal of Oncology (Cancer Study):
"The evidence for a connection between phone use and cancer is clear and convincing. The more you use phones and the greater the number of years you have them, the greater the risk of brain tumours."
http://www.rfsafe.com/its_time_to_be_rf_safe.htm

Also check these other links:
http://www.cure-guide.com/Natural_Health_Newsletter/Cell_Phone_and_Cordless_Phone_/cell_phone_and_cordless_phone_.html
Cordless Phone Dangers
http://www.tetrawatch.net/science/dect.php

An important note: The “best answer” cites the FDA as the final authority. But remember, the FDA is controlled by lobbyists who speak for corporations that want to sell more products, even if they are harmful. Would you even buy a cell phone, would millions of Americans, if they were told about the cancer risks? Of course not. Would you let your child have a cell phone if it could cause them to develop brain tumors 20 years down the road? It’s preventable, and you no longer have the excuse of ignorance, because you have been told the truth, and you can find out more for yourself if you took the time to investigate further, and protect your family.

Yes cordless phones give off less rf radiation then cellphones but you have to keep in mind that rf has never been proven to be harmfull. If you are concerned with rf you should be more worried about the amount of radiation in the 2.4 ghz band from wifi then cordless phones.